Problem:
Saving custom post type throws Error:
You cannot use this slug because it is already used or a reserved word. Please choose a different slug.
Solution:
As the error reads, you must have created either any post, page, content template or view any any other entity with the slug "tablet-application" or it's a reserved slug.
WordPress do not allow duplicate slugs and slugs should be unique. Can you please try to find where you are using the slug tablet-application" and then rename that slug and then it will allow you to create entity with your desired slug.
A user reported that in the form to add a new post some custom script is included to append an empty default select field option. But, if the same code is used in the post edit form, it doesn't show the field's saved value.
Solution:
Suggested some changes to the custom script, so that it doesn't change the selected option in the select field.
